Mr Trump’s chief strategist Steve Bannon and senior adviser Jared Jushner were also present at the briefing at his Floria resort, Mar-a-Lago, where he is currently entertaining the Chinese President Xi Jinping and his delegation.

President Trump formally announces the military action in Syria in retaliation for the attack on civilians (AP)

The photo was taken about 45 minutes after the missiles landed and was posted by Spicer on Twitter with the caption: “WH photo (ed for security): @potus receives briefing on #syria military strike fr Nat Security team, inc @vp , SECDEF, CJCS via secure VTC.

The picture emerged as a tense emergency meeting of the UN security council got under way following the US air strike.

At the meeting, the US envoy to the UN Nikki Haley warned that America may take further action and said her country would not stand by when chemical weapons were used as it was in its “vital interest” to stop their proliferation.

Syrian ally Russia accused the US of encouraging “terrorists” with its unilateral actions and promised to strengthen its ally’s anti-aircraft defences.

It also said it was closing down a hotline with the US designed to avoid collisions between their air forces over Syria.

At least six people are reported to have been killed in the US missile strikes early on Friday. US officials said the base was used to launch a chemical weapons attack that killed dozens of civilians on Tuesday.

It is believed 89 people, including 33 children and 18 women, died in the suspected nerve agent attack in the rebel-held town of Khan Sheikhoun. Syria has denied using nerve gas.